Method of fabricating liners for closure caps



.1. M. MCGEE 2,809,568

METHOD oF FABRICATING LINERS FoRcLosURP: CAPs Oct. 15, 1957 3 Sheets-Sheet 1 Filed Jan. 20, 1955 Oct. 15, 1957 J. M. MCGEE 2,809,568

METHOD 0F FABRICATING LINERs FOR CLOSURE CAPs- Filed Jan. 2o, .1955 :s sheets-sheet 2 Oct. 15, 1957 J. M. MGGEE 2,809,568

METHOD OF`FABRICATING LINERS FOR CLOSURE CAPS Filed Jan. 20, 1955 3 Sheets-Sheet 3 United States Patent f METHGD 0F FABRICATING LINERS FOR CLOSURE CAPS John M. McGee, Evansville, Ind., assigner to Bernardin Bottle Cap Company, Inc., Evansville, Ind., a corporation of Indiana Application ianuary 20, 1955, Serial No. 4S3,032

2 Claims. (Cl. 93--1.3)

The invention relates to self-venting liners for closurecaps for receptacles containing uids under pressure and apparatus for and method of producing said liners.

Heretofore, a groove or channel was `cut diametrically across one face of a liner-disk under the top of a closurecap to provide a vent in the liner which usually is formed of cardboard sheeting, for reducing pressures in the container when they become excessive. In fabrication, a continuous channel was cut in a strip which produced a channel extending diametrically across the disk, so that its bottom of uniformly reduced thickness left an area entirely across the liner which was not backed by the cap. This area of reduced thickness was subject to failure from fatigue or became weakened or ruptured when subjected to pressure for long periods.

One object of the invention is to provide an improved vent structure in the liner-disk which resists such fatigue and avoids such weakness and which can be economically and expeditiously produced.

Another object of the invention is to provide apparatus for and a method of expeditiously and economically cutting vent-grooves which are interrupted by lands so that the disk at its center will minimize fatigue and rupture in the areas of reduced thickness.

Other objects of the invention will appear from the detail description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

ln the drawings:

Fig. l is a vertical section of a closure for a receptacle including a seaiing disk embodying the invention;

Fig. 2 is a plan view of the disk;

Fig. 3 is a plan view of an elongated strip from which the disks are severed, and showing the channels cut therein, the location of the circular cuts for severing the disks from .the strip being shown in dotted lines, and some of the disks removed from the strip; Y

Fig. 4 is a section of the apparatus for fabricating the liners, taken on line 4 4 of Fig. 5;

Fig. 5 is a perspective View of the underside of the guide for the strip of paper underlying the platen;

Fig. 6 is a plan view of said apparatus;

Fig. 7 is a section taken on line 7-7 of Fig. 6;

Fig. 8 is a side elevation of said apparatus; and

Fig. 9 is a section taken on line 9 9 of Fig. 6.

The closure comprises a sheet metal cap generally designated iii which includes a top-wall 11 and a depending skirt 12. A screw-thread 13 is formed in the sln'rt and is adapted to be secured on a mating screw-thread iii on the container 15 and to force the cap onto the container. The container has a rim 16 which functions as a seat for a liner or sealing disk, generally designated i8. The disk 18 is circular in contour and produced from a strip of cardboard. of uniform thickness or with coplanar faces.

The lower face of the liner is planar so that its margin normally seats on the rim 16 and forms a seal between ice the liner and the container when the liner is clamped on the container by the cap. The upper face of the liner abuts the top-wall 11 of the cap 10. The lowerface 4of the liner is usually provided with a coating which is impervious to gases and liquids in the container.

The upper face of .the liner-disk has a formation for self-venting when the pressures in the container become excessive or exceed a predetermined limit. This formation is produced by cutting away some of the cardboard from one face of the disk to form channels with bottom areas of reduced wall thickness which, when exed by such pressures, permit the escape of gases between .the rim 16 of the container and the bottom face of the margin of the liner. The top-face of the liner is formed with a pair of diametrically aligned channels 20 which are produced by cutting away material from said face. Channels 26 have parallel sides 21 with bottom-walls 22 which are lof uniform and reduced wall-thickness. The outer ends of channels 20 intersect the edge of the disk. From said edge, the channels extend radially inward and terminate at an intermediate land 24 of the full thickness of the disk. The inner ends of the channels 2i) are of gradually decreasing depth to gradually increase the wallthickness at the inner ends of the channels which merge into the land. The areas of bottoms 22 of reduced wallthickness are flexible angularly from their inner ends upwardly to the edge of the disk by excess pressures. This construction minimizes fatigue or .rupture from the land to the edge of the disk for the escape of gases between the outer end of the exed areas and said surface while the land is supported by the top wall of the cap.

The liners are produced from a continuous or elongated strip a of cardboard. Two longitudinal rows a2 and a3 of grooves ai. are formed by removing the cardboard stock to a depth ranging from .02 to .04, for example, over a width of 3/16" to 1A. Each groove al is of sufcient length to form a channel 20 in two adjacent disks plus the scrap left in the strip. The lands between the grooves are from Ms to 1A in length between said grooves. The grooves al and the land in row a2 are staggered relatively to ,the grooves and lands in row a3. The disks are severed from the strip by circular cuts relatively to the grooves a1 and the lands 24, as indicated by dotted lines in Fig. 3. This manner of forming the grooves in and securing the disks from the strip a minimizes waste and facilitates fabrication of the liners.

The liners are fabricated from the strip a which is drawn from a coil (not shown) of cardboard over a pair of cutter tools to serially cut grooves ai in the underface of the strip.

A11 exempliiication of mechanism for producing these liners comprises; a suitable supporting structure 39; stationary guide-means for the strip a which includes a platen 32 overlying the strip a and a plate 33 underlying said strip; a pair of feed-rolls 35 and 36 which intermittently advance the strip longitudinally in a predetermined stroke; a pair of rotary milling-tool cutters 37 and 38 for removing material from the strip a to form the grooves a1 in the rows a2 and a3 respectively; mechanism for disengaging the cutters from the strips for forming the lands 24 between the grooves ai; and mechanism for severing the liner-disks from the strips. The strip a is slidably confined between platen 32 and plate 33 for the operation of the cutters 37 and 3S and is intermittently advanced. Mechanism is provided for imparting intermittent unidirectional rotation to the feedrolls, and comprises; a power-driven shaft 43 journalled in structure 3i); a crank or wrist-pin 44 driven by said shaft; a pitman 45 pivoted to pin 44 and to an arm 46 which is pivotally supported on a shaft 4S which is journalled on the structure 3G; a gear 50 which is secured described.

Y a parallel shaft 61.

to oscillatie with arm 46; a toothed rack-bar 52 which is slidably mounted in a stationary guide 53, is reciprocated by and meshes with gear 58; a ratchet-wheel 56 secured to rotate feed-roll 35; a spring-pressed pawl 54 pivoted to and reciprocated by rack-bar 52, and engaging ratchetwheel 56; and a pair of meshing gears 57 between and secured respectively to rotate `with feed-rolls 35 vand 36. Shaft 43-is continuously driven from a suitable source of power. VDuring successive revolutions'of crank-pin 44 it will operate pitman 45 to oscillate arm 46 and gear 50. Said gear 50 will impart reciprocatory strokes of predetermined length to rack-bar 52 and pawl 54. During each forward stroke of rack-bar 52, it will impart Va stroke to pawl 54 for rotating the feed-rolls to advance the strip a the distance vequal Vto length of a groove a1 plus the lengthof a land 24 forV forming a groove a1 and a land 24 in each of the rows a2 and a3. During each retractile stroke of rack-bar 52, the feed-rolls will remain idle for severing the liners from the strip a, as hereinafter The cutters 37 and 38are of rotary mill-cutting type, 1%" in diameter, and are constantly driven at approximately 4500 R. P. M. Said cutters are normally positoned to cut grooves a1 in the strip a to a depth ranging from .02 to .04 for forming parallel-sided grooves a1 in the strip, withY bottom-walls of reduced thickness. The cutter 37 is mounted to cut grooves a1 in row a2 in staggered relation to the grooves cut in the row a3. Cutter 37V is xed on a shaft 60 and cutter 38 is xed on Shafts 60Yand 61.are journalled in a pillow-block 62 which is mounted on a vertically slidable plate V64. The upper portion of cutter 38 passes 'through a Vslot 86 in the plate 33 to intersectthe under- 'face of a strip a and form the grooves a1 in row a2.

The upper portion of cutter 37 rotates through a slot 87 in the plate 33 to intersect the underface of a strip` a and form the grooves a1 in row a3. YPlate 33 is formed with cross grooves 88 for the escape of the cuttings. Mechanism for driving the cutters comprises; an electric motorv 89 mounted on plate 64 with a shaft which drives a'pulleyfor driving a V-belt 91 which drives a pulley 92 on the shaft 60 of cutter 37, and another pulley which is driven Yby the shaft of said motor and drives a V- belt 93 which drives a pulley 94 on the shaft 61 of cutter V38.

During each forward stroke of strip a, the cutters willV remain engaged with strip a to form a groove a1 and disengageV from the strip a to form Vthe landY between theV successive grooves a1.

The supporting plate 64 on Vwhich the Vcutters are mounted, is supported to slide vertically for engaging and disengaging the cutters and the strip. Studs 66 are iixedlyV mounted .on a Ystationary bed 67 and sleeves 68 which are vertically slidable on said studs, are screwthreaded to plate 64. Stop-nuts 69 on studs 66 limit the upward movement of plate 64 and the cutters by coil springs 70. By adjustment of nuts 69 the lift of the cutters and depth of the groovesal'formed by the-cutters Y can be varied as desired. The plate 64 is depressed against the force of springs 70 to disengage the cutters from strip a, interrupt the forming of the groovesal in strip a, and to form the lands 24, Ythe strip a being confined against vertical movement between platen Y32 and plate 33. Y Y YDuring each forward stroke of strip a, the cutters are lowered away from the bottomface of said strip to form a land 24 betweenA successive grooves a1 in each row. This occurs in timed relation with the advance of the strip for producing alternating grooves a1 and lands in succession in each series. The cutters 37 and 3S, shafts 60 and .61, and pillow-block 62 are vertically movable with plate 64 to move the cutters into and out of cutting engagement with the under face'of the strip a, by fthe depression of plate 64; Coil springs 70 around sleeves andbearing62 until sleeves 68 are arrested Vby nuts 69 to position ther cutters to cut the grooves Va1 of the desired depth in the strip a and permit the cutters to be lowered for the lands 24 between successive grooves a1.

Mechanism is provided for intermittently lowering plate 64 for disengaging the cutters from the strip and interrupting the channels a1 in the Vstrip a to form the lands 24, and comprises; a wheel 74 fixed to rotate with shaft 48 and provided with cam-ribs 75, and a plate 77 fixed to the top of the vertically slidable plate 64 for vertical movement therewith and provided with an abutment 78 engageable by cam-ribs 75 to depress plate 64 and lower bearing 62, shafts 60 and 61, and cutters 37 and 38 against the force of springs 70; a ratchet-wheel which the cutters are mounted for vertical movement` will be depressed during a portion of each forward strokeY of strip a for a suflcient period to produce a land between the ends of successive grooves a1. After each depression of the cutters, a cam-rib 75 will rotate off the abutment 78 and springs 70 will lift the cutters into engaged relation with the strip of paper a for a succeeding cut ofthe desired depth. In this manner, the cutting mechanism will be shifted to alternately cut grooves a1 and interrupt Y the cuts for lands 24 to form a series of grooves a1 for each channel 20 in each of two adjacent'disks whichV are thereafter cut from the strip with a land 24 at the center of each disk.

The-camribs 75 are timed to the paper travel so that during each intermittent advance of the strip, a groove a1 and a -land will be produced in one face of the strip.Y

The vertical movement of the cutters into and out ofthe strip a causes the ends of grooves a1 to conform to the path of the periphery of the cutters, and the depth'ofjthe` end portions of grooves a1 to be tapered or graduated toward the adjacent lands. 'Ihe bottom of said inner portions -Will have tapered or gradually increasing wall-thickness toward the land. This renders Ythe bottoms of the channels 20 in the fabricated disks angularly Vflexibleewith greater displacement at the edge of the disk when subjected to excess pressures inthe container. The pressure of gases llexes the bottom-walls of channels 20 at an upward and outward inclination for the escape of the gases between the'outer end of the bottom areas of reduced wallthickness adjacent the edge of the disk and the rimof the container.

After the strip a advances beyond the feed-rolls and during its stationary cycles, the'liners 18 will be punched Vfrom the strip .by mating male andfemale dies and 91 Vwhich are'diagrammatically shown in-Fig. 4 andY disposed preventing stresses in the bottom of the channels which Y to simultaneously punch a circular disk in each of the staggered rows a2 and a3 from the strip a. This punching severs the disks from'the strips so that successive disks in the rowswllhavea circular edge, a central land 24 and diametrically aligned channels 20- extending from the land result'infa'tigue-or rupture by. excessive pressures.

The invention exemplifies a closure for a receptacle withV self-,venting liner-disk which avoids failure from fatigue inthe areas of reduced wall-thickness which-'are respon sive to excess pressures in the receptacles; which can be economically and expeditiously fabricated. The invention also exempliies apparatus for and method of fabricating said disks economically and expeditiously.

The invention is not to be understood as limited to the details set forth since these ma) be modiiied within the scope of the appended claims without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

l. That improvement in fabricating self-venting linerdisks for use in sealing receptacles, which comprises; feeding an elongated or continuous strip of flexible sheet material having planar faces in a rectilinear longitudinal path, intermittently removing material from one face of the strip to ferm a row of longitudinally aligned parallel-sided channels with bottom-walls of reduced thickness to render them flexible by excess pressures in the container, and leaving lands of full thickness between contiguous ends of the channels, and severing circular disks from the strip by circular cuts intersecting successive channels with a land between the contiguous ends of said channels substantially at the center of the disk.

2. That improvement in fabricating self-venting linerdisks for use in sealing receptacles, which comprises; feeding longitudinally an elongated or continuous strip of exible material having planar faces, in a rectilinear path; intermittently removing from one face of the strip material to form plural staggered rows of longitudinally aligned parallel-sided channels with bottom-walls and areas of reduced thickness to render them exible by excess pressures in the container, with lands of full thickness between contiguous ends of the channels in the rows respectively; and severing circular disks from staggered portions of the strip to intersect contiguous ends of the channels in the rows of the strip by circular cuts intersecting successive channels in the rows respectively with lands between the contiguous ends of the channels in said rows substantially at the cen ters of the disks.

References Cited in the tile of this patent UNITED STATES PATENTS 2,042,851 Knowles June 2, 1936 2,102,157 Keaney et al Dec. 14, 1937 2,193,412 Southam Mar. 12, 1940 2,235,101 Enkur Mar. 18, 1941 2,265,862 Rosentreter Dec. 9, 1941 

